/*
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at 
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *  
 */

using System;
using java = biz.ritter.javapi;
using org.apache.commons.collections;

namespace org.apache.commons.collections.comparators
{


    /**
     * Decorates another Comparator with transformation behavior. That is, the
     * return value from the transform operation will be passed to the decorated
     * {@link Comparator#compare(Object,Object) compare} method.
     * 
     * @since Commons Collections 2.0 (?)
     * @version $Revision: 7148 $ $Date: 2011-06-05 14:51:23 +0200 (So, 05. Jun 2011) $
     * 
     * @see org.apache.commons.collections.Transformer
     * @see org.apache.commons.collections.comparators.ComparableComparator
     */
    public class TransformingComparator : java.util.Comparator<Object>
    {

        /** The decorated comparator. */
        protected java.util.Comparator<Object> decorated;
        /** The transformer being used. */
        protected Transformer transformer;

        //-----------------------------------------------------------------------
        /**
         * Constructs an instance with the given Transformer and a 
         * {@link ComparableComparator ComparableComparator}.
         * 
         * @param transformer what will transform the arguments to <code>compare</code>
         */
        public TransformingComparator(Transformer transformer)
            : this(transformer, new ComparableComparator())
        {
        }

        /**
         * Constructs an instance with the given Transformer and Comparator.
         * 
         * @param transformer  what will transform the arguments to <code>compare</code>
         * @param decorated  the decorated Comparator
         */
        public TransformingComparator(Transformer transformer, java.util.Comparator<Object> decorated)
        {
            this.decorated = decorated;
            this.transformer = transformer;
        }

        //-----------------------------------------------------------------------
        /**
         * Returns the result of comparing the values from the transform operation.
         * 
         * @param obj1  the first object to transform then compare
         * @param obj2  the second object to transform then compare
         * @return negative if obj1 is less, positive if greater, zero if equal
         */
        public virtual int compare(Object obj1, Object obj2)
        {
            Object value1 = this.transformer.transform(obj1);
            Object value2 = this.transformer.transform(obj2);
            return this.decorated.compare(value1, value2);
        }

        public virtual bool equals(object obj)
        {
            return Equals(obj);
        }

    }

}